Device for filling containers with liquids



DEVICE FOR FILLING CONTAINERS WITH LIQUIDS Filed April 6, 1959 2 Sheets-Sheet 1 INVENTOR. 0644/12! A! 2167 Za ATTO/PA/EJ/S Dec. 25, 1962 c. H. ELLETT 3,070,137

DEVICE FOR FILLING CONTAINERS WITH LIQUIDS Filed April 6, 1959 2 Sheets-Sheet 2 FIG. 2

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United States Patent Ofiice A eaters! Patented Dec. 25, 1962 3,070,137 DEVICE FOR FILLING CONTAINERS WITH LIQUIDS Charley H. Ellett, Huntsville, Ala., assignor to Thiokol Chemical Corporation, Trenton, N.J., a corporation of Delaware Filed Apr. 6, 1959, Ser. No. 804,273 Claims. (Cl. 141-226) This invention relates to the filling of a container with liquid from a supply source by means of a movable delivery conduit. More particularly it relates to an apparatus which provides for the movement of the discharge end of the delivery conduit so as to maintain it close to the surface of the liquid in the container being filled.

In the transfer of viscous liquids, such as partially polymerized liquid polymers from a supply source to a mold, it is very diflicult to avoid occlusion of air which remains trapped in the transferred material. One very serious source of this occluded air is related to the position of the discharge end of the delivery conduit. If the discharge end is positioned above the surface of the liquid, the liquid will splash trapping the air immediately above the surface and form pockets of air within the liquid. On the other hand, if the discharge end is far below the surface, a considerable quantity of the viscous material is apt to temporarily cling to the end of the: delivery conduit and then fall back into the material in the mold and cause air to be entrapped. It is essential for homogeneity of the polymer that these air pockets be avoided. Also, it is necessary for this homogeneity that the viscous liquid flow outward from the discharge end only radially so as to provide maximum opportunity for disengagement of bubbles of trapped air from the liquid. Thus, the discharge end of the delivery conduit must be moved relative to the container being filled so as to maintain the discharge end of the conduit close to the liquid surface. Where the viscous liquid is of a hazardous nature remote controlled transfer must be provided for. No such ap paratus was available for either automatic or remotely controlled automatic transfer of viscous fluids without entrapment of air and/or causing heterogeneity of the transferred fluid mass.

It is, therefore, an object of this invention to provide an apparatus which will overcome the deficiencies of prior art devices. It is a further object to provide a remotely controlled apparatus, which will permit filling of a container with a highly viscous fluid without entrapment of air in the transferred fluid. Other objects of the invention will become apparent from the following discussion and appended claims.

The foregoing objects have been generally achieved in accordance with this invention by an apparatus having a movable conduit for delivering the viscous liquid from a supply source to a container to be filled and a liquid level sensing element attached to the delivery conduit. This liquid level sensing element is positioned adjacent to the discharge end of the delivery conduit and produces a signal as a function of the degree of its immersion, and a corresponding degree of immersion of the end of the conduit in the liquid. This signal is used in the apparatus to maintain the position of the discharge end of the delivery conduit immersed, but close to the surface of the liquid in the container being filled with the viscous liquid.

For a more complete understanding of the invention, reference should now be made to the drawings in which:

FIGURE 1 diagrammatically shows the apparatus of the invention;

FIGURE 2 shows in vertical section the pneumatically operated cut-off valve positioned in the delivery conduit;

FIGURE 3 diagrammatically shows an enlarged view of the discharge end of the delivery conduit and the attached liquid level sensing element in partial vertical section; and,

FIGURE 4 is a diagrammatic view of the pneumatic control responsive to the pressure developed. in the liquid level sensing element.

Referring now to FIGURE 1, the viscous liquid 10 is stored in supply tank 12, which has a removable cover 14. The supply tank 12 is positioned on elevator table 16 which is vertically moved in response to hydraulic actuation of elevator apparatus 22. The viscous liquid 10 flows by gravity from the supply tank 12 to the container 24 to be filled through a delivery conduit 26 and usually a pressure fluid is applied to the surface of the liquid in tank 12 to accelerate the rate of flow. The flow through delivery conduit 26 is controlled by a flex valve 28 in the conduit which opens the conduit during a filling operation and closes the conduit when the container is filled. The supply tank 12 is at all times positioned above container 24 and is lifted vertically with respect to the container by the elevator apparatus 22. Elevator 22 is raised by pumping oil 30 from the oil storage tank through pump 34 and oil lines 36 and 38 into the elevator cylinders 20. The pumped oil 36 exerts pressure against the elevator pistons 18 and the elevator table 16 rises. The flow of oil 39 from the pump 34 is controlled by a normally closed solenoid valve 40 in the line 38 which is operated when electric current is supplied to the solenoid windings. The oil 30 is drained from the elevator cylinders 20 by opening gate valve 42. This provides for the return of elevator table 16 to its lowered position, there'- by also lowering supply tank 12. A pressure relief valve is connected between the outlet from the pump 34 and tank 30 and in front of control valve 40 and bleed valve 4-2.

Thus, to fill the container 24 flex valve 28 is opened by closing the line 43 for supplying pressure fluid to the valve 28 and bleeding off the pressure fluid acting on valve 28 by opening a valve 44 in the supply line. The viscous liquid 10 then flows into container 24 through delivery conduit 26, the lower outlet end of which extends into container 24 and is maintained close to the surface of the liquid 10 therein. This spatial relationship of the discharge end 46 and the liquid surface is maintained within acceptable limits by response to pressure developed in a liquid level sensing element 48. When the discharge end 46 is maintained close to the surface, the flow of liquid does not trap air within the body of liquid.

Referring now to FIGURE 3, the liquid level sensing element 48 is in the form of a hollow hell with an open bottom which communicates with a pressure regulator 50 through a tube 52. The bell shaped element 48 provides a relatively large area subjected to the liquid to increase its sensitivity to a rise in the liquid level and the large opening permits the viscous liquid to drain quickly. The lower end of the bell also is formed with a sharp edge to facilitate draining of the viscous liquid therefrom. Sensing element 48 is mechanically secured to the delivery conduit 26 by means of clamp 54 so that the open bottom of the bell is located close to, but slightly above, the discharge end 46 of the delivery conduit. The pressure regulator 50, see FIGURE 1, also is connected to a source of air under pressure, illustrated as an air tank 56, by means of supply line 58 and to a pressure responsive switch 69 by an air line 62. Closing of the contacts of switch 61? energizes solenoid of a relay switch 66 which supplied current from power source 68 to the motor 70 of the oil pump 34 and'to solenoid valve 40.

A cut-off sensing element 72 is positioned close to the open end of container 24. The element 72 is similar in construction to sensing element 48 and consists of a hollow tube which communicates with a second pressure regulator 74 through a tube 76. Regulator 74 also is connected to air tank 56 by a branch of supply line 58 and to a pressure operated switch 78 by line 80. The main switch 82 for the apparatus comprises on and off push buttons 82a and 82!). Push buttons 82a when closed turn on light 84 and actuate a normally open solenoid actuated valve 86 which closes the line 43 that communicates between flex valve 28 and air tank 88. Push button 82b when pressed opens the electric circuit to the light 84 and solenoid so that valve 86 opens to supply fluid from air tank 88 to operate the flex valve and close conduit 26 from the supply tank 12.

Referring now to FIGURE 2, the flex valve 28 is shown in cross-section and applied to a flexible section of delivery conduit 26. The valve 28 comprises a housing 202 having end plates 204 which together with diaphragms 206 attached thereto provide expansion motors at opposite sides of the delivery conduit 26. The end plates 204 are each connected to supply line 43 so that when valve 86 is open, air pressure exerts a force on diaphragms 206 and expands them to a position indicated. Diaphragms 2il6ar'e connected to valve elements 210 which move toward each other to pinch the flexible section of delivery conduit 26, thus, to prevent further flow through conduit 26.

The pressure regulators 50 and 74 may be any suitable type available on theopen market which are responsive to slight variations in pressure in the medium to be controlled to produce relatively large variations in the pres sure of an air stream used to control the medium. One such regulator 50 is illustrated in FIGURE 4 which is especially sensitive to slight variations in pressure for operating the pressure responsive switch 60. Regulator 50, as shown in FIGURE 4, comprises a chamber 501 to which tube 52 is attached and having a large diaphragm 502 at one side movable in response to a small increase in pressure in the liquid level sensing element 48 resulting from a rise in the liquid level of the material in the container 24. The motion of the diaphragm 502 is multiplied by lever 503 which, in turn, moves a flapper 504 for controlling the flow of a small stream of air from a nozzle 505 in the pressure regulator. Air from a source (tank 56) enters the pressure regulator 50 through an air inlet port 506 and flows from an outlet 507 at a pressure controlled by a ball valve 508 and diaphragm 509. When flapper 504- restricts the flow of air from nozzle 505, an increased pressure on the diaphragm 509 opens ball valve 508 to increase the pressure of the air flowing from outlet 507. One side of diaphragm 509 is subjected to the pressure of the small stream fed to nozzle 505 through a port 510 and the opposite side of the diaphragm is vented through an exhaust port 511. Thus, an increase in pressure in the liquid level sensing device 48 is transmitted to the pressure regulator 50 which operates as a relay for producing an increase in the pressure of air supplied to the pressure operated switch 60.

The pressure operated'switch 60 also may be of any conventional type and as illustrated in FIGURE 1, comprises an expansible bellows 601 connected to the outlet port 507 of the pressure regulator 50. Bellows 601 mounts a bridging contact 602 which is loaded by a spring 603 opposing the action of the bellows. Spring 603 is adjustable to cause the switch contact 602 to bridge fixed contacts 603 and 604 at a predetermined air pressure as controlled by the pressure regulator 50. Thus, upon a predetermined increment of rise of the liquid level of the liquid 10 in the container 24, switch 60 is closed to close relay switch 66 and operate the elevator mechanism 22 and raise the lower end of the delivery conduit 26 relative to the liquid level.

The pressure regulator 74 is identical with the pressure regulator 50 for increasing the pressure of the control air in conduit 80 when the container 24 becomes filled. The pressure responsive switch 78 also is of the same construction as the switch 60 except that an increase in pressure opens the switch to cause the valve 86 to open. In

other words, switch 60 is normally open and closed by an increase in pressure while switch 78 is normally closed and opened by an increase in pressure.

The operation of the apparatus to fill a container 24 will now be considered. Prior to filling however, it is, of course, understood that the liquid 10 to be transferred to the container 24 is first pumped into the supply tank 12 and under conditions so as to avoid occlusion of air in the liquid 10. The container 24 to be filled is placed under the delivery conduit 26 and the elevator table 16 is lowered to its lowest position prior to a pouring operation by opening bleed valve 42 in oil line 38. After the table 16 has been lowered, valve 42 is closed. The discharge end 46 of the delivery conduit should extend into the container 24 and close to its bottom. Operation of push button 82a of switch 82 closed a circuit through the contacts of the normally closed pressure switch 78 to energize solenoid valve 86 and thus close supply line 43 which extends from air tank 88. The air is then bled from supply line 43 by opening valve 44 to open flex valve 28. The liquid 10 then flows into container 24 by means of delivery conduit 26. Preferably, pressure is applied to the surface of the liquid 10 in tank 12 to accelerate the flow of liquid through delivery conduit 26. As the liquid level in the container 24 rises the open lower end 302 of the bell-shaped sensing element 48 becomes immersed. A pressure then develops 'within sensing element 48 as a result of the continued rise of the liquid level. This pressure increase is transmitted to pressure regulator 50- through'sensing line 52. Air tank 56 supplies air at a control pressure, for example, 17 pounds per square inch, to pressure regulator 50 through supply line 58. Referring now to FIGURE 4, the air under pressure in line 58 enters the regulator 50 through port 506 and a stream of air flows from the outlet port 507 to line 62 at a pressure functionally related to the pressure in line 52 from the sensing element 48. As the air pressure increases in line 52 due to the rise of the liquid level in the interior of sensing element 48, the diaphragm 502 is expanded and rocks lever arm 503 which, in turn, moves the flapper 504 toward nozzle 505 and increases the pressure of the fluid leaving outlet port 507 and entering line 62.

Referring again to FIGURE 1, the increase in pressure within supply line 62 acts through bellows 601 of pressure switch 60 against the action of spring 603 to actuate bridging contact 602 into engagement with fixed contacts 603 and 604 to close the switch. Current then flows through the solenoid winding of relay switch 66 which closes its power contacts. Power is thereby supplied to the motor 70 of the oil pump 34 and to the solenoid valve 40 thereby opening the oil line 38. The oil 30 is pumped from the oil reservoir 32 through the now open oil line 38 into the elevator cylinders 20 forcing the pistons 18 upward. This raises the supply tank 12 lifting the delivery conduit 26 toward the surface of the liquid 10 in container 24. This reduces the pressure within sensing element 48 Which, acting through pressure regulator 50, decreases the pressure acting on the bellows 601 so that spring 603 opens the switch contacts. Opening of switch 60 de-energizes relay 66, cutting off the power to motor 70 and the solenoid valve 40. This sequence is continued again and again as demanded by the control circuitry responsive to the air pressure de veloped within the liquid level sensing element 48.

When the level of the liquid 10 in the container rises into the inner volume of the cut-off sensing element 72 a pressure increase is transmitted to the pressure regulater 74 by supply line 76. Pressure regulator 74 is identical in construction with that of regulator 50 except that an increase in pressure opens the switch contacts to deenergize the solenoid valve 86. Valve 86 moves to its normally open position and supply air from tank 88 furnishes a high pressure, e.g., pounds per square inch, through now open line 43, to flex valve 28 thereby closing it and preventing further flow of liquid in delivery conduit 26. The filling operation is now completed and the filled container 24 can be removed.

The apparatus of the invention provides a number of advantages, some of which are apparent and others perhaps not as easily recognized. First of all, it is possible to transfer highly viscous liquids, such as partially polymerized liquid polymers to a mold where the polymerization is to be substantially completed without entrainment or entrapment of air within the mass of the transferred liquid material. Secondly, this transfer of liquid can be accomplished without vertical Stratification, which might occur if the discharge end of the delivery conduit was not maintained close to the surface of the liquid in the container or mold being filled. Further, the pneumatic sensitive system is so simple that there is no likelihood of fouling the control device by clogging. Finally, it is possible to fill a container with a hazardous fluid as a remotely controlled and fully automatic operation.

While a single embodiment of the invention is herein illustrated and described, it will be understood that changes may be made in the construction and arrangement of elements without departing from the spirit or scope of the invention. Therefore, without limitation in this respect, the invention is defined by the following claims.

I claim:

1. An apparatus for filling a container with a liquid comprising, in combination, a supply tank mounted above said container for holding a supply of said liquid, said delivery tank having a delivery conduit extending into said container to provide for gravity induced flow of said liquid into said container, elevator means for relatively moving said tank and said container to increase the vertical spacing therebetween and cause said delivery conduit to be withdrawn from said container as liquid flows thereinto, said elevator means comprising a platform for said supply tank, piston means connected to said platform, cylinder means enclosing and defining the travel of said piston means, a pump for supplying hydraulic fluid to said piston means under pressure, an electrically operated valve for controlling flow of hydraulic fluid to said piston means, a pneumatic liquid level sensing element having a bell shape mounted on said delivery conduit with an open end positioned approximately at the discharge end thereof, said sensing element having air therein and adapted to be partially immersed in the liquid in said container whereby the air pressure in said sensing element varies as a function of the degree of immersion of said sensing element, pressure operated switch means connected to said bell-shaped element and responsive to the pressure therein for controlling the electric operated valve regulating the flow of hydraulic fluid to said piston means whereby said elevator means raises said supply tank until the pneumatic pressure in said sensing element decreases, a second pneumatic liquid level sensing element positioned at the desired full level of. said liquid container, and cut-ofl valve means for stopping delivery of said liquid responsive to pressure developed within said second sensing element.

2. An apparatus for casting a polymer in a container while in a viscous liquid phase without entrapment of air comprising, in combination, a supply tank mounted above said container for holding a supply of said liquid, said supply tank having a delivery conduit extending into said container, motor means for relatively moving said tank and container to increase the vertical spacing therebetween and cause said delivery conduit to be withdrawn from said container as liquid flows thereinto, a bellshaped pneumatic liquid level sensing element with an open end mounted on said delivery conduit and positioned approximately at the discharge end thereof, said sensing element having air therein and partially immersed in the liquid in said container whereby the air pressure in said sensing element varies as a function of the degree of immersion of said sensing element, means responsive to the pressure in said sensing element for regulating said motor means to maintain the discharge end of'said delivery conduit just beneath the surface of the liquid in said container as said container is filled with said liquid whereby to prevent the formation of any air bubbles in the casting or a void by the removal of the delivery conduit, a separate bell-shaped stationary pneumatic liquid level sensing element with an open end at the desired cutoff level, valve means for controlling flow from the tank through the delivery conduit, and means responsive to the pressure variation in said stationary pneumatic sensing element for controlling the valve means located on said delivery conduit intermediate between the juncture of said delivery conduit with said supply tank and said discharge end of said delivery conduit.

3. An apparatus for filling containers with a viscous liquid which avoids entrapment of air comprising, in combination, a liquid supply means having a delivery conduit adapted to extend into a container for receiving said liquid, a bell-shaped liquid level sensing element rigidly mounted on said delivery conduit for movement therewith and having an open end positioned adjacent to and above the end of the delivery conduit, said sensing element having means to produce a pneumatic pressure functionally related to the degree of immersion of said bell-shaped sensing element in said liquid, a pressure responsive element connected to and operated by the pneumatic pressure produced by immersion of said bell-shaped sensing element, and means controlled by said pressure responsive element and connected to move said delivery conduit to maintain its discharge end close to the surface of the liquid as said container is filled with said liquid whereby to prevent formation of air pockets in the liquid in the container.

4. An apparatus for filling containers with a liquid comprising, in combination, a liquid supply means having a delivery conduit adapted to extend into a container to which said liquid is delivered, a tubular sensing element closely adjacent the delivery conduit and having an open end, a clamp for rigidly mounting the tubular sensing member on the conduit with its open end above the end of the conduit a distance substantially equal to the desired degree of immersion of the delivery conduit, said tubular sensing element having means to produce a pressure proportional to the degree of immersion of its open end in said liquid, means for relatively moving the discharge end of the delivery conduit and container, a responsive element connected to and operated by the pressure produced in said tubular sensing element for controlling said means for relatively moving said delivery conduit and container for regulating said position of the end of said delivery conduit relative to the surface of the liquid in said container as it is filled with said liquid.

5. An apparatus for casting a polymer in a container while in a viscous liquid phase without entrapment of air comprising, in combination, a supply tank mounted above said container for holding a supply of said liquid, said supply tank having a delivery conduit extending into said container, motor means for relatively moving said tank and container to increase the vertical spacing therebetween and cause said delivery conduit to be withdrawn from said container as liquid fiows thereinto, a bellshaped pneumatic liquid level sensing element rigidly mounted on said delivery conduit for movement therewith and having an open end positioned adjacent to and above the discharge end of the conduit, said sensing element having air therein and having means to produce a pneumatic pressure functionally related to the degree of immersion of its end in said liquid, means responsive to the pressure in said sensing element for regulating said motor means to maintain the discharge end of said 7 delivery conduit just beneath the surface of the liquid in said container as said container is filled with said liquid whereby to prevent the formation of air bubbles in the casting.

References Cited in the file of this patent UNITED STATES PATENTS 1,881,106 Vogt et al Oct. 4, 1932 8 Copeland Oct. 12, 19-48 Gricar et a1 Nov. 24, 1953 Williams Feb. 11, 1958 Freeman Aug. 11, 1959 Ring Mar. 29, 1960 

